title: Ecology of Leptospira interrogans in Norway rats (Rattus norvegicus) in an inner-city neighborhood of Vancouver, Canada.
abstract: BACKGROUND
  Leptospira interrogans is a bacterial zoonosis with a worldwide distribution for which rats (Rattus spp.) are the primary reservoir in urban settings. In order to assess, monitor, and mitigate the risk to humans, it is important to understand the ecology of this pathogen in rats. The objective of this study was to characterize the ecology of L. interrogans in Norway rats (Rattus norvegicus) in an impoverished inner-city neighborhood of Vancouver, Canada.
  
  
  RESULTS
  Trapping was performed in 43 city blocks, and one location within the adjacent port, over a 12 month period. Kidney samples were tested for the presence of L. interrogans using PCR and sequencing. A multivariable model was built to predict L. interrogans infection status in individual rats using season and morphometric data (e.g., weight, sex, maturity, condition, etc.) as independent variables. Spatial analysis was undertaken to identify clusters of high and low L. interrogans prevalence. The prevalence of L. interrogans varied remarkably among blocks (0-66.7%), and spatial clusters of both high and low L. interrogans prevalence were identified. In the final cluster-controlled model, characteristics associated with L. interrogans-infection in rats included weight (OR = 1.14, 95% CI = 1.07-1.20), increased internal fat (OR = 2.12, 95% CI = 1.06-4.25), and number of bite wounds (OR = 1.20, 95% CI = 0.96-1.49).
  
  
  CONCLUSIONS
  Because L. interrogans prevalence varied with weight, body fat, and bite wounds, this study suggests that social structure and interactions among rats may influence transmission. The prevalence and distribution of L. interrogans in rats was also highly variable even over a short geographic distance. These factors should be considered in future risk management efforts.
authors.affiliation: School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada. Chelsea.Himsworth@gov.bc.ca
authors.forename: Chelsea G
authors.initials: CG
authors.lastname: Himsworth
authors.forename: Julie
authors.initials: J
authors.lastname: Bidulka
authors.forename: Kirbee L
authors.initials: KL
authors.lastname: Parsons
authors.forename: Alice Y T
authors.initials: AY
authors.lastname: Feng
authors.forename: Patrick
authors.initials: P
authors.lastname: Tang
authors.forename: Claire M
authors.initials: CM
authors.lastname: Jardine
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.forename: Sunny
authors.initials: S
authors.lastname: Mak
authors.forename: John
authors.initials: J
authors.lastname: Robinson
authors.forename: David M
authors.initials: DM
authors.lastname: Patrick
mesh_terms: D000818:Animals; D002170:Canada / Q000453:epidemiology; D016000:Cluster Analysis; D005260:Female; D007921:Leptospira interrogans / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D007922:Leptospirosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D008297:Male; D016133:Polymerase Chain Reaction; D015995:Prevalence; D051381:Rats; D012376:Rodent Diseases / Q000453:epidemiology* / Q000382:microbiology*; D017422:Sequence Analysis, DNA